C语言，杨辉三角输出数字是第几个

Question

#include<stdio.h>
int jiecheng(int m){
    if(m==0)
    return 1;
    else
    return m*jiecheng(m-1);
}
int zuhe(int m,int n){
    int a;
    a=jiecheng(m)/jiecheng(n)/jiecheng(m-n);
    return a;
}
int main(){
    int m;
    scanf("%d",&m);
    int i,j;
    for(i=2;i<=100000000;i++)
    {
        for(j=1;j<=i;j++)
        {
            if(zuhe(i,j)==m)
            {
                printf("%d",(i-1)+0.5*(i-1)*(i-2)+j);
                return 0;
            }    
        }
    }
    return 0;
}

这个程序为什么不实现输入一个数，输出这个数在杨辉三角中是第几个数啊？

Answer 1

main 函数的 printf 语句中，printf("%d",(i-1)+0.5*(i-1)*(i-2)+j); 的括号不正确。
而且，你这个循环数量太大了，循环会很慢

#include <stdio.h>

int jiecheng(int m) {
    if (m == 0)
        return 1;
    else
        return m * jiecheng(m - 1);
}

int zuhe(int m, int n) {
    int a;
    a = jiecheng(m) / (jiecheng(n) * jiecheng(m - n)); // Corrected calculation
    return a;
}

int main() {
    int m;
    scanf("%d", &m);
    int i, j;
    for (i = 1; i <= 100; i++) {  // Reduced the range for faster computation
        for (j = 0; j <= i; j++) {
            if (zuhe(i, j) == m) {
                printf("The number %d is found in row %d of Pascal's Triangle.\n", m, i);
                return 0;
            }
        }
    }
    printf("The number %d is not found in Pascal's Triangle.\n");
    return 0;
}